N21923

iTrader: (8)

Got a car with an LS1, long tubes, and a small 222* cam. When driving and I push the clutch in, the idle goes up to 2000rpms... most of the time. After about 10-15 seconds, the idle drops down to 800 or so rpms. I have HP tuners and can use the 2 way controls to manually bring the idle down, but it won't do it by itself.

I've done some basic PE, VE and MAF tuning, but that's it. My tuning makes the engine run smoother, better gas mileage, and no more black smoke when revving, but I still have the idle issue.

Ideas?

WeathermanShawn

iTrader: (1)

Mmm..Sounds like too much air in the Throttle Follower (P/N) and/or your decay rate is too slow. Remember, P/N airflow is when the clutch is engaged or the transmission is in neutral.

Did you change those tables from stock?

N21923

iTrader: (8)

Didn't change those values. The engine is in an RX7 and the clutch pedal switch isn't hookedup. I'll see what happens when I change those rates. Thanks.

BlueStreak362

iTrader: (8)

having the exact same problem now with my H/C/I motor, what increments would you guys reccomend changing them in?

WeathermanShawn

iTrader: (1)

If it is really when the clutch is depressed and Idle rises or hangs, then it is usually the Throttle Follower in P/N. You usually don't have to suspect any interaction from the Throttle Cracker..since in most OS's it is zero airflow.. (P/N).

But, as usual it is not as simple as just changing the Throttle Follower and/or its decay. Since a lot of these so-called 'Idle Airflows" are present at non-idle and are cumulative..you still have to go back to the Desired Airflow Table first. I am running the 'other' software suite, so my terminology may differ than the one you are using. Desired Airflow, followed by Throttle Follower, and Throttle Cracker all need to be precisely tuned. It could take a short story to go through all of it.

Basically dial in Desired Airflow using your software applications (RAFIG, etc..). I try to run a minimum of Air in the Throttle Cracker, and use the stock Throttle Follower Airflow..but I manipulate the airflow multiplier and its decay rate to my personal preference.

The bottom line is that you probably have way too much air in any of the above three..but most likely it is too much air in the Throttle Follower at the TPS% setting and/or RPM and especially in the P/N Table(s).

Sorry, for the long answer. Its not easily understood..or no one would have the problem.

Good luck..

5.7 ute

Log the various airflow pids & see which is the culprit. Beats guessing IMO.
FWIW, even with no TC airflow in the tune I have come across a strange hanging idle where increasing the TC decay fixed it.

N21923

iTrader: (8)

I found one of the problems... the car had an auto tune on it, not a manual. I used the PCM that came with the pullout, but appearantly, it was mixed up somewhere. After flashing a manual program on it, most of the problems when away.

00T/AWS6

iTrader: (17)

Not to thread hijack, my car did something very similar but only slightly. It was maybe 1100 instead of 900 when i pushed clutch in to go neutral. After i added a 92/92 it worsened to like 2000. Is it possible that this is the same problem the OP has or vacuum leak haha. I will be gettin hptuners soon so also subscribing for what to look at.

35th camaro

my 402 would idle to 1200 until my car came to a complete stop, what would cause this.

WeathermanShawn

iTrader: (1)

OP, glad to hear you got it figured out. That would explain your problem.

To the other readers, as 5.7ute said, logging all the airflow parameters is pretty easy. It is one of the best ways to determine which airflow parameter is active and whether it is at idle, clutch in, in gear., P/N you name it.

All the symptoms described are usually too much air. You just have to log to really know. Good point about vacuum leaks. That can cause grief too..

Congrats on figuring it out..

offroadfury6

iTrader: (8)

hmmm...my TA does the same... clutch in- revs to about 2k....then idles back down to 800

Eagle02

iTrader: (20)

Sounds like your follower values are off. Idle tune it!

offroadfury6

iTrader: (8)

Still same issues...haven't got ahold of a tuner yet, hahaha...

so I need to change the throttle follower P/N values?

still doing same thing, higher rev for a few seconds on start-up and when clutch pushed in revs to maybe 2k for 15 secs...same thing when A/C is on too..